‘Cautiously optimistic’: Human trials for coronavirus vaccine

Doug Hendrie

26/05/2020 5:04:42 PM

The Australian trials are underway in Melbourne and Brisbane.

The Alfred Hospital
The Australian trials – which will take place in facilities linked to Melbourne’s Alfred Hospital and the Royal Brisbane and Women’s Hospital – will include 131 healthy adults.

The vaccine candidate by US vaccine biotech company Novavax is the latest to enter human testing, with more than 100 vaccines under development around the world.
The Australian trials – which will take place in facilities linked to Melbourne’s Alfred Hospital and the Royal Brisbane and Women’s Hospital – will include 131 healthy adults aged 18–59.
The news comes after the Coalition for Epidemic Preparedness (CEPI) announced it will put up to $590 million into the Novavax research.
This candidate, NVX-CoV2373, is a ‘subunit vaccine’, in which harmless copies of spike proteins from the SARS-CoV-2 coronavirus are grown in vats before being injected to create antibodies which may be able to protect against infection by the virus.
Novavax has used similar techniques in devising vaccine candidates against two other dangerous coronaviruses: severe acute respiratory syndrome (SARS), which emerged in 2003; and Middle East respiratory syndrome (MERS) in 2012.
The subunit approach is an established vaccine production technique, used in vaccines against human papillomavirus (HPV), shingles and other viruses.
Inventor of the HPV vaccine Professor Ian Frazer has predicted that the subunit approach is the most likely to bear fruit.
By contrast, two other prominent candidate vaccines developed by companies Moderna and BioNTech both rely on mRNA vaccines – a promising but so far unproven approach to vaccine development that tricks the body into producing viral proteins, which then engender an antibody response.
German microbiologist Professor Isabelle Bekeredjian-Ding told Horizon magazine that mRNA is ‘a very unique way of making a vaccine and, so far, no [such] vaccine has been licensed for infectious disease’.
Infectious diseases expert Dr Paul Griffin will oversee the Australian trial for clinical trial operator Nucleus Network , which he told newsGP is ‘really exciting’.

‘With the gravity of situation with COVID-19 and our need for a vaccine, any vaccine candidate entering trials is a big step forward,’ he said. 
‘To do any studies in humans, you have to be really confident of the data. This vaccine in particular has really good animal data – it’s really impressive, from a safety and efficacy point of view. That’s why we’re confident to do this in humans.
‘I’m cautiously optimistic. We don’t know if it will provide the protection we need, but we know it’s the right product to take to Phase 1 and assess as quickly as possible.’
Dr Griffin has had a ‘pleasing response’ to calls for volunteers.
‘People understand the significance of these trials,’ he said.
‘This has no live virus in it; it’s been cleverly manufactured using one of the proteins on the surface of the virus. There’s absolutely no risk from the vaccine.
‘We expect from preclinical and animal trials that this will induce a really good immune response that will generate protective immunity. That’s what we hope.
‘But we will carefully assess the data and if it doesn’t support moving forwards, that’s what will happen.’
But Dr Griffin said that even if the candidate does not produce the desired response, it could still be useful.
‘With a lot of these vaccines, if one candidate [isn’t effective], it can be tweaked to address those issues,’ he said.
‘If we get some protection but not enough, we could change the adjuvant, the dose, or slightly change the antigen. Any trials we do will certainly help inform us.’
While some experts have questioned whether a vaccine will ever provide adequate protection against the SARS-CoV-2 coronavirus, Dr Griffin is more hopeful.
‘These arguments rely on flawed concepts,’ he said.
‘People say we don’t have vaccines for other coronaviruses, such as those that cause a cold. But the impact of a cold is so small and the mortality incalculable that you’d never convince an investor or grant body to set up a study into cold-causing coronaviruses.
‘With the SARS coronavirus, there were lots of promising candidates – but they didn’t proceed through all the clinical trial stages before the virus was brought under control with infection control.
‘During this pandemic, lots of manufacturers have leveraged their existing SARS vaccines. So when people say we won’t have a vaccine for this virus, it just doesn’t stack up.
‘We don’t want to be ahead of ourselves. It needs to be proven in Phase 1, 2 and 3 trials. But every vaccine that progresses through each of these stages is a huge step forward.
‘It concerns me that anti-vaxxers are objecting to the coronavirus vaccine when it doesn’t even exist yet. That shows they’re objecting for the sake of it – it’s not based on facts or evidence.
‘Others are concerned at how quickly these are being developed, but the rigor around these vaccines is greater than ever before because of how much attention there is.’
Early results are expected in July.
However, Novavax research chief Dr Gregory Glenn has said his company is making doses in parallel ‘in anticipation that we’ll be able to show it working’ by the end of the year.
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